Immense, ever-increasing quantities of solid wastes are generated each day which presents major collection, disposal and nuisance problems. The cost of disposal of solid wastes ranks third amongst the cost of public schooling, highways and general municipal expenses.
The quantity of trash that accumulates daily in large cities is truly staggering. It is estimated that each individual generates about 4 to 6 pounds of trash per day. Furthermore, the trash from industrial sources amounts to an equivalent of an additional 5 to 10 pounds per person per day. The average cost of disposal is approximately $5 to $10 per ton of trash.
Conventional methods of disposal, such as landfill and incineration, are becoming prohibitively expensive and are creating serious pollution problems.
Landfill areas, for instance, are becoming increasingly fewer in number and further from the municipalities where the principal amount of trash is generated.
In the past, there have been developed various methods for the treatment of solid waste for recovery of values contained therein for recycle back to the economy. A general method of processing waste material involves segregating organic matter from inorganics which include metals, concrete, bricks, glass and the like. The predominantly organic fraction may be processed for recovery as saleable materials such as paper pulp, and the balance pyrolized to form char and a gaseous stream containing chemicals which may be condensed as saleable commodities. Char has an economic value of its own. As to the predominantly inorganic fraction, ferrous materials may be separated magnetically prior to, or following, separation of the organics. The remaining inorganics are comminuted by crushing or grinding into particles of fine size. Some may be separated by screening, and others may be separated by heavy media separation techniques.
Crushed particulate glass particles can be of value if recovered from such waste material. Typically, the predominantly organic fraction described above contains some glass particles; and the predominantly inorganic fraction contains glass particles as well as other inorganic and organic constituents.